Nettel made the Stereax in two plate sizes; 4.5x10.7 cm and 6x13 cm. Both have a focal-plane shutter with speeds up to 1/1200 second, which is self-capping (like that of the Deckrullo-Nettel). The 6x13 cm camera has a folding wire-frame viewfinder; the smaller model has a folding optical finder (according to McKeown). The 4.5x10.7 cm camera also has a front cover-flap, which opens like a folding bed (but does not support the lens board). Like other Nettel cameras, focusing is by varying the strut extension, but on this model, this is done by a knob on the lens standard, not on the camera body. The 6x13 cm camera has the normal Nettel focusing mechanism, with the struts adjusted from the camera body, and with the end of one strut forming the pointer of a focus scale in a slot in the top of the camera. The 6x13 cm camera can be arranged for panoramic pictures, using the whole plate, as well as for stereo, and the wire frame finder is usable for both formats.
In its listing as a Contessa-Nettel camera (i.e. after 1919), McKeown describes the Stereax as a continuation of the Nettel Deckrullo Stereo, but both models seem to have been made alongside each other by both Nettel and Contessa-Nettel.
The cameras were available with a range of different lenses, including Nettel's own Nettel Anastigmats in the Nettel period, and Carl Zeiss Tessars. Both standard, black leather-covered and tropical models were made.
- 4.5x10.7 cm Stereax by Nettel, with CZJ 6.5 cm f/4.5 Tessar lenses, sold at the second/third Westlicht Photographica Auction, in May 2003.
- McKeown, James M. and Joan C. McKeown's Price Guide to Antique and Classic Cameras, 12th Edition, 2005-2006. USA, Centennial Photo Service, 2004. ISBN 0-931838-40-1 (hardcover). ISBN 0-931838-41-X (softcover). p.216 and 715.
- Tropical 6x13 cm Stereax with 12 cm f/4.5 Tessars; the camera is by Contessa-Nettel, according to the auctioneer's listing, though the lens serial numbers date them to 1930, after the merger that formed Zeiss Ikon; sold at the seventh Westlicht auction, in May 2005.
- Tropical 6x13 cm Stereax by Contessa-Nettel, with 9 cm f/4.5 Tessar and 7.5 cm f/5.5 Xenar lenses, and a film pack adapter, sold at the fifteenth Westlicht auction, May 2009; several pictures.
- Tropical 6x13 cm Stereax by Contessa Nettel, with 8.3 cm f/4.5 Skopar lenses, in Compur shutters; neither the speeds nor the aperture controls of the two shutters are linked, and the lens serial numbers are far apart, suggesting these are not the original lenses. Sold at the 23rd Westlicht auction, on 25 May 2013.